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Last Updated October 29, 2008

I intend on revising this description due to a particular question regarding the definition of a weld increment. I will hope to explain better in the next revision to this explanation.

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Joint Efficiencies and Nameplate Stamping

REF: ASME Section VIII -1 2007 Edition

 Paragraphs UW-3, UW-11, UW-12, UW-51 and UW-52

The following sample vessel illustrates how to calculate the efficiencies of a seamless section according to UW-12 when UW-11(a)(5)(b) is utilized.

The vessel is made from 3 components -- A rolled and welded shell and two seamless elliptical heads. The long seam in the shell and the head to shell welds are spot radiographed according to rules for radiography of paragraph UW-52. All welds are Type 1 butt welds. What is E for the rolled shell, and for the seamless heads? Efficiencies of seamless sections are found in UW-12(d) - the two heads are seamless. [All quotes are from ASME VIII, 2007 Edition:

UW-12(d): Seamless vessel sections or heads shall be considered equivalent to welded parts of the same geometry in which all category A welds are Type No 1. For calculations involving circumferential stress in seamless vessel sections or for thickness of seamless heads, E = 1.0 when the spot radiography requirements or UW-11(a)(5)(b) are met. E = 0.85 when the spot radiography requirements of UW-11(a)(5)(b) are not met, or when the category A or B welds connecting the seamless vessel sections of heads are Type no 3, 4, 5 or 6 of Table UW-12.

The sample vessels welds are Type 1 so the bit about Type 3, 4,5 or 6 welds can be ignored, but UW-11(a)(5)(b) can be utilized.

UW-11(a)(5)(b) can not be read on its own. UW-11, UW-11(a) and UW-11(a)(5) are also needed as reference in order to understand the context of UW-11(a)(5)(b). To quote UW-11(a) -- Full Radiography

The following welded joints shall be examined radiographically for their full length.

Starting with UW-11(a)(5):

All Category A and D butt welds in vessel sections and heads where the design of the joint or part is based on a joint efficiency permitted by UW-12(a), in which case:

and finally -- UW-11(a)(5)(b):

Category B or C butt welds [but not including those in nozzles or communicating chambers except as required in (2) above] which intersect the Category A butt welds in vessel sections or heads or connect seamless vessel sections or heads shall, as a minimum meet the required for spot radiography in accordance with UW-52. Spot radiographs required by this paragraph shall not be used to satisfy the spot radiography rules as applies to any other weld increment.

Definitely a mouthful, start simplifying UW-11(a)(5). A Cat A weld is a long seam. Combine it with UW-11(a)….

All long seam welds in heads or shells shall be type 1 or type 2 and shall be radiographed for their full length.

Simplify paragraph UW-11(a)(5)(b)

Spot radiographs required by this paragraph shall not be used to satisfy the spot radiography rules as applies to any other weld increment.

This means that the radiography used to satisfy paragraph UW-11(a)(5)(b) cannot be used to satisfy other weld increments that have spot radiography rules applied to them. For example. If the vessel was to be stamped RT-3 then all welds are required to be spot radiographed.  You cannot use the radiographic shots for welds satisfying RT-3 stamping. Paragraph UW-11(a)(5)(b) radiography MUST be separate shots……

…..so to continue on…….

Ignoring the possibility of nozzles or communicating chambers intersecting welds, we get the following:

Category B or C butt welds which intersect the Category A butt welds in vessel sections or heads or connect seamless vessel sections or heads shall, as a minimum meet the required for spot radiography in accordance with UW-52.

Combining the simplified statements (the possibility of intersecting chambers and nozzles has been ignored) -- 3 simple requirements:

To meet UW-11(a)(5)(b) for the long seam in question:

(1) Fully radiograph the long seam or choose seamless materials

(2) Long seam must be Type 1 or Type 2

(3) Spot or fully radiograph the joining circ weld

For the vessel shell, the long seam is not fully radiographed, and is not a seamless section, so UW-11(a)(5)(b) is not met for the shell long seam.

For each vessel head, the long seam in the head is “assumed” to be Type 1 and is seamless, so UW-11(a)(5)(b) is met for the imaginary head long seam.

Getting back to the sample vessel and UW-12. Imaginary (assumed) Type 1 seams have been added to the heads:

UW-12(d) is readable once UW-11(a)(5)(b) is known. To paraphrase for the sample vessel: The imaginary welds in the head have an efficiency of 1.0 if UW-11(a)(5)(b) is met and 0.85 if it is not. For the sample vessel, the head efficiency is 1.00. The shell long seam efficiency is read directly from table UW-12 - it is 0.85.

 

A Google search on the term " UW-11(a)(5)(b) " yielded the following results............. and of course my site........

From EngTips.com Forums thread

http://www.eng-tips.com/viewthread.cfm?qid=154335

From HSB Global Standards Pressure Points Newsletters

http://www.hsbglobalstandards.com/hsbct/public.nsf/1/0625294d5d4c4c2285256d57005febc8/$FILE/PPjune00.pdf

http://www.hsbglobalstandards.com/hsbct/public.nsf/1/0625294d5d4c4c2285256d57005febc8/$FILE/PPNov00.pdf

http://www.hsbglobalstandards.com/hsbct/public.nsf/1/0625294d5d4c4c2285256d57005febc8/$FILE/PPnov01.pdf

From the National Board Summer 2006 Bulletin (starting on page 3)

http://www.nationalboard.org/NationalBoard/Publications/Bulletins/Pdf/SU06.pdf

For the following below:

All joints are of Type 1 and all by the same welder

Combined weld increments are less than 50 ft in length

Please note that the UW-11(a)(5)(b) paragraph is used to determine the joint efficiency of the Long Seams in vessel sections or heads.

Examples with seamless heads and welded shells.

RT Nameplate stamping per UG-116 is not required because radiography is not performed

No RT circumferential seams (head to shell welds)

No RT longitudinal seam (shell)

Assume Type 1 Longitudinal Seam in Seamless Head

UW-11(a)(5)(b) NOT met

E head = 0.85 from UW-12(d)

E shell = 0.7 from Table UW-12

RT Nameplate stamping per UG-116 is RT-3

ALL welds must have spot RT to meet RT-3 stamping reqts.) Additional RT is necessary since spot radiography required by paragraph UW-11(a)(5)(b) shall not be used to satisfy other weld increments such as that specified by UW-11(b)

Spot RT circumferential seams (head to shell welds)

Spot RT longitudinal seam (shell)

Assume Type 1 Longitudinal Seams in Seamless Heads

UW-11(a)(5)(b) is satisfied for Head longitudinal seams ONLY

E head = 1.00 from UW-12(d)

E shell = 0.85 from Table UW-12

(Note the additional spot RT on the "other" head circumferential seam. This is necessary to satisfy the RT-3 stamping, keep in mind that IF the combined circumferential weld increments are less than 50 feet, and one spot RT was performed on one head to shell circumferential weld, UW-11(a)(5)(b) would still be satisfied, BUT the nameplate RT stamping would become RT-4

RT Nameplate stamping per UG-116 is RT-1

Full RT circumferential seams (head to shell welds)

Full RT longitudinal seam (shell)

Assume Type 1 Longitudinal Seams in Seamless Heads

UW-11(a)(5)(b) is satisfied

E head = 1.0 from UW-12(d)

E shell = 1.0 from Table UW-12

RT Nameplate stamping per UG-116 is RT-2

 

Spot RT circumferential seams (head to shell welds)

Full RT longitudinal seams (shell)

Assume Type 1 Longitudinal Seam in Seamless Head

UW-11(a)(5)(b) is satisfied for ALL long seams

E head = 1.0 from UW-12(d)

E shell = 1.0 from Table UW-12

(Note that the additional spot RT on the "other" head circumferential seam is not necessary to satisfy BOTH the RT-2 stamping and UW-11(a)(5)(b) since the combined weld increment is less than 50 feet. IF more than one welder performed the work and the combined circumferential weld increments are more than 50 feet, another spot RT is required to maintain RT-2 stamping AND satisfy UW-11(a)(5)(b)

,

RT Nameplate stamping per UG-116 is RT-4

Full RT circumferential seams (head to shell welds)

Spot RT longitudinal seam (shell)

Assume Type 1 Longitudinal Seams in Seamless Heads

UW-11(a)(5)(b) is satisfied for Head longitudinal seams ONLY

E head = 1.00 from UW-12(d)

E shell = 0.85 from Table UW-12

RT Nameplate stamping per UG-116 is RT-4

No RT circumferential seams (head to shell welds)

Full RT longitudinal seam (shell)

Assume Type 1 Longitudinal Seams in Seamless Heads

UW-11(a)(5)(b) is NOT satisfied

E head = 0.85 from UW-12(d)

E shell = .85 from UW-12(a)

You may ask, WHY is the shell longitudinal seam efficiency only 0.85 when full RT is performed on that seam? Please read UW-12(a) and you will understand that in order to claim 1.0 efficiency of the longitudinal seam in question you must perform a "quality" spot RT on the intersecting weld.

Examples with seamless heads and seamless (pipe) shells

RT Nameplate stamping per UG-116 is not required because radiography is not performed

No RT circumferential seams (head to shell welds)

Assume Type 1 Longitudinal Seams in Seamless Sections

UW-11(a)(5)(b) is NOT satisfied

E head = 0.85 from UW-12(d)

E shell = 0.85 from UW-12(d)

RT Nameplate stamping per UG-116 is RT-3

Note that ALL welds must have spot RT to meet RT-3 stamping reqts.) Additional RT is necessary since spot radiography required by paragraph UW-11(a)(5)(b) shall not be used to satisfy other weld increments such as that specified by UW-11(b)

Spot RT circumferential seams (head to shell welds)

Assume Type 1 Longitudinal Seams in Seamless Sections

UW-11(a)(5)(b) is satisfied

E head = 1.0 from UW-12(d)

E shell = 1.0 from UW-12(d)

NOTE: A vessel made from seamless vessel sections and seamless heads, with the total circumferential weld increments less than 50 feet, one spot RT, on either of the head seams, will satisfy UW11 (a) (5) (b) BUT if you choose not to perform spot RT on the other circumferential weld in accordance with RT-3 stamping criteria, the RT nameplate stamping would become RT-4. 

RT Nameplate stamping per UG-116 is RT-1

Full RT circumferential seams (head to shell welds)

Assume Type 1 Longitudinal Seams in Seamless Sections

UW-11(a)(5)(b) is satisfied, but not necessary since full RT

E head = 1.0 from UW-12(d)

E shell = 1.0 from UW-12(d)

Examples with two shells (seamless and welded)  

All joints are of Type 1 and all by the same welder

Combined weld increments are less than 50 ft in length

 

 

 

 

Examples with seamless shells and seamless heads

RT Nameplate stamping per UG-116 is not required because radiography is not performed

Two seamless pipes/shells/heads

No RT circumferential seam (shell to shell weld)

No RT head circumferential seams (both head to shell welds)

UW-11(a)(5)(b) is NOT satisfied

E shell = 0.85 from UW-12(d)

E heads = 0.85 from UW-12(d)

RT Nameplate stamping per UG-116 is RT-4

(Note that in order for RT-3 stamping, ALL welds must have spot RT to satisy UW-11(b) Therefore, additional RT is necessary since spot radiography required by paragraph UW-11(a)(5)(b) shall not be used to satisfy other weld increments such as that specified by UW-11(b).

Two seamless pipes/shells/heads

Spot RT circumferential seam (shell to shell weld)

No RT head circumferential seams (both head to shell welds)

(Note that combined weld increments are less than 50 feet and one spot RT is adequate) If combined weld increments exceeded 50 feet, an additional spot RT is required for each additional 50 ft of circumferential weld.

UW-11(a)(5)(b) is satisfied

E shell = 1.0 from UW-12(d)

E heads= 1.0 from UW-12(d)

RT Nameplate stamping per UG-116 is RT-4

Two seamless pipes/shells

Full RT circumferential seam (shell to shell weld)

No RT head circumferential seams (both head to shell welds)

(Note that combined circumferential weld increments are less than 50 feet) If combined circumferential weld increments exceeded 50 feet, calculation is required to verify one 6 inch RT exposure for each additional 50 ft of circumferential weld.

UW-11(a)(5)(b) i s satisfied

E shell = 1.0 from UW-12(d)

E heads = 1.0 from UW-12(d)

 

 

 

Examples with welded shells and seamless heads

RT Nameplate stamping per UG-116 is not required because radiography is not performed

Two welded shells and seamless heads

No RT circumferential seam (shell to shell weld) 

No RT head circumferential seams (both head to shell welds)

No RT longitudinal seam (shell weld)

UW-11(a)(5)(b) is NOT satisfied

E Shell = 0.7 from Table UW- UW-11(a)(5)(a) and (b)

E heads = 0.85 from UW-12(d)

E shell = 0.85 from UW-12(d)

RT Nameplate stamping per UG-116 is RT-4

Two welded shells and seamless heads

No RT circumferential seam (shell to shell weld)

No RT head circumferential seams (both head to shell welds)

Spot RT longitudinal seam (shell weld)

UW-11(a)(5)(b) is NOT satisfied

E Shell = 0.85 from UW-11(a)(5)(a) and (b)

E heads = 0.85 from UW-12(d)

RT Nameplate stamping per UG-116 is RT-4

You may ask, WHY is the shell longitudinal seam efficiency only 0.85 when full RT is performed on that seam? Please read UW-12(a) and you will understand that in order to claim 1.0 efficiency of the longitudinal seam in question you must perform a "quality" spot RT on the intersecting weld

Two welded shells and seamless heads

No RT circumferential seam (shell to shell weld)

No RT head circumferential seams (both head to shell welds)

Full RT longitudinal seams (shell welds)

UW-11(a)(5)(b) is NOT satisfied

E shell = 0.85 from UW-12(a)

E heads = 0.85 from UW-12(d)

RT Nameplate stamping per UG-116 is RT-4

(Note that in order for RT-3 stamping, ALL welds must have spot RT to satisfy UW-11(b) Therefore, additional RT is necessary since spot radiography required by paragraph UW-11(a)(5)(b) shall not be used to satisfy other weld increments such as that specified by UW-11(b).

Two welded shells and seamless heads

Spot RT circumferential seam (shell to shell weld)

No RT head circumferential seams (both head to shell welds)

Spot RT longitudinal seams (shell welds)

UW-11(a)(5)(b) is NOT satisfied

E Shell = 0.85 from UW-11(a)(5)(a) and (b)

E heads = 0.85 from UW-12(d)

RT Nameplate stamping per UG-116 is RT-2

(Note as defined in UG-116 for RT-2 stamping, circumferential welds must have spot RT to satisfy UW-11(a)(5)(b) NOT UW-11(b) Therefore, additional RT is only necessary if combined weld increments of the circumferential welds exceeded 50 feet, where an additional spot RT is required for each additional 50 ft of circumferential weld.

Two welded shells and seamless heads

Spot RT circumferential seam (shell to shell weld)

No RT head circumferential seams (both head to shell welds)

Full RT longitudinal seams(shell welds)

(Note that combined circumferential weld increments are less than 50 feet and one spot RT is adequate) If combined weld increments of the circumferential welds exceeded 50 feet, an additional spot RT is required for each additional 50 ft of circumferential weld.

UW-11(a)(5)(b) is satisfied

E Shell = 1.0 from Table UW-12 and UW-11(a)(5)(a) and (b)

E heads = 1.0 from UW-12(d)

RT Nameplate stamping per UG-116 is RT-4

(Note that in order for RT-1 stamping, ALL welds must have full RT.

Two welded shells and seamless heads

Full RT circumferential seam (shell to shell weld)

Full RT longitudinal seams (shell welds)

No RT head circumferential seams (both head to shell welds)

(Note that combined circumferential weld increments are less than 50 feet) However, If combined circumferential weld increments exceeded 50 feet, calculation is required to verify one 6 inch RT exposure for each additional 50 ft of circumferential weld.

UW-11(a)(5)(b) is satisfied

E Shell = 1.0 from Table UW-12 and UW-11(a)(5)(a) and (b)

E heads = 1.0 from UW-12(d)

Please take note:

The reason UW-11 (a)(5)(b) is applied to welded sections/courses of a vessel is because of paragraphs UW-11(a)(5)(a) and (b)

The paragraph UW-11(a)(5) states that "....all Category A or D butt welds in vessel sections or heads where the design of the joint is based on a joint efficiency permitted by UW-12(a) in which case: ...."